Circuit breaker



' June 22, l1943. H.. D.`DORFMAN 2,322,285.

CIRCUIT BREAKER Filed nay 29, 1941 2 sheets-sneer. 1

Jum22,1943i f H, D. DQRFMAN 2,322,235-

voIRcUIT BREAKER Patented June 22, 1943 ENT OFF! E CIRCUIT BREAKER Hiller D. Dorfman, Forest Hills, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 23, 1941, Serial iNo. 395,832

(Cl. `ZOU-116) 14 Claims.

This invention relates to circuit breakers and more particularly to circuit breakers of the type which are manually operated, and also automatically operated in response to predetermined overload conditions in the circuit.

One object of the invention is to provide an improved circuit breaker of simple, compact and relatively inexpensive construction, and which is dependable in operation Another object of the invention is to provideV an improved circuit breaker having a compact operating mechanism automatically operable to cause the contacts to open a relatively large distance.

Another object of the invention is to provide a circuit breaker with improved and simplilied mechanism for causing the contacts to close with a snap action and to apply pressure to the contacts after they are closed.

' Another object of the invention is to provide an improved circuit breaker having a switchmember operable in response to predetermined circuit conditions to move a contact member to open the circuit and manual means to move the contact member to open the circuit independently of the movement of the switch member.

Another object of the invention is to provide an improved circuit breaker with a switch member having open and closed positions and having a Contact arm thereon movable therewith to open and close the circuit, wherein the contact arm is movable to open and close the circuit Without displacing the switch member from its closed position.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims, the invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best undertsood from the following detailed description of one embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figfl is a vertical sectional View of a circuit breaker constructed in accordance with the invention, the section being taken substantially on line l-I, of Fig. 2, and the breaker'being shown in the closed circuit position;

Fig. 2 is a rear'elevational view of the circuit breaker with the cover plate removed to Show some of the parts;

Fig 3 is a vertical sectional view similar to Fig. 1 but showing the circuit breaker in the tripped open position.; and

Fig. 4 is a vertical sectional View similar to Fig. l but showing the breaker mechanism in the manually opened condition.

Referring to Figures l and 2 of the drawings the circuit breaker includes a base of molded insulating material having side walls |3 molded integral therewith, a llat cover plate 5 secured to the side walls by means of suitable screws |1, an operating mechanism indicated generally at I9, a trip device indicated at 2|, a stationary contact 23, and a movable contact 25.

The movable Contact 25 is mounted on a contact lever 21 pivotally supported on a pivot 29 in the free ends of a pair of switch arms 3|. The switch arms 3| are rotatably mounted on a pivot 33 supported in the ends` of a U-shaped bracket 35 secured to the base the switch arms being joined for movement together by the pivots 29 and 33. Since the switch arms 3| are secured for movement together they will hereinafter be referred to in the description as the switch arm.

An angular bracket 31, secured to the switch arm 3| adjacent the pivoted end,. is provided with an aperture 39 through which projects one end of a toggle link 4| the other link of the toggle comprising one arm of the contact lever 21. A compression spring 43 surrounding the link 4l and compressed between the bracket 31 and a washer 44 supported on .the link by a pin 4,5, maintains the notched end of the link in engagement with the notched end of the contact lever 21.

In the closedY position the toggle 21-4| is over center to the right of the pivot 29 of the lever 21, as indicated in Fig. l, in which position the spring 43 serves to apply pressure to the contacts.

V The stationary contact 23 is secured to the inner end of aconductor 41 suitably secured t0 the base Hand extending outside of the casing to provide a terminal 49. The contact lever 21 is electrically connected to a conductor 5| by means of a flexible shunt conductor 53. A bimetal element 55 is secured to the opposite end of the conf ductor 5| by a screw 51 which serves to secured both the' birnetal element 55 and the conductor 5|y E to the base |i. A U-shaped piece of insulating material 55 insuiates the' bracket 35 from the conductor 5|. The free end of the bimetal 55 carries an angular connection 59 which is connected to a'conductor 6| by a flexible shunt conductor 63. Theconductor 6| has a portion projecting outside of the casing to form a terminal B5 which, with the terminal 49, serves to connect the breaker in an electrical circuit.

The electrical circuit'through the breaker extends from the terminal 49 through the conductor 61, the stationary contact 23, the movable contact the Contact lever 21y the flexible shunt conductor 53, the conductor 5I, the bimetal element 55, the iexible shunt conductor 63, and the conductor 5l to the terminal 65.

A releasable operating lever 61 pivotally supported on a pivot pin 69 seated in bearing slots in the side walls I3 of the base I I is biased in a counterclockwise direction by an operating spring 1I tensioned between said operating lever and the pivot 33 for the switch arm 3 I. The operating lever 61 is normally restrained in the position in which it is shown in Fig. l by a curved latch member 13 mounted in a block 14 of insulating material secured on the upper end of said lever engaging a latch 15 on the free end of the bimetal element 59. The latch 15 is in the form of a screw which serves also as a convenient means for adjusting the tripping point of the breaker. The other end of the lever 61 is provided with a cam slot 11 operatively engaging a pin 19 carried by the switch arms 3|.

When the bimetal element 55 is heated a predetermined amount in response to overload current flowing through the circuit of the breaker, it flexes in a direction to unlatch the operating lever 61 whereupon the spring 1I rocks said lever counterclockwise about its pivot 69. The configuration of the cam slot 11 of the lever 51 is such that, acting through the pin 19, it rocks the switch arm 3| in a counterclockwise direction about the pivot 33 to separate the contacts 25-23. During this movement a shoulder 8| on the lever 61 strikes the end of the contact lever 21 opposite the contact 25. Continued counterclockwise movement of the lever 61 cams the toggle 21-4I over center in a direction to cause the contacts to open with a snap action and to cause greater separation of the contacts. The movement of the contact lever 21 in the direction to open the contacts is limited by said lever striking the formed over end 83 of the conductor 5I. The parts are shown in their tripped open positions in Fig. 3.

After the breaker has been operatedin response to an overload current it is necessary to relatch the operating lever G1 before the circuit breaker can be closed. For this purpose a manual operating member 85 is provided. The lever 95 comprises a pair of bell cranks 81 pivoted on a pivot pin 89 supported in the side walls I3 of the casing. The bell cranks 81 straddle the switch arm 3| and the contact lever 21 and are connected by a yoke 9| at their ends adjacent the contact lever. The other arms of the bell cranks are joined by a stud 93.

A manual operating handle 95 extending through an opening 91 in the base is pivotally mounted on a pivot 99 supported in the base. A projection I9! integral with the handle 95 extends through an opening in the yoke 9| and a spring |03 is compressed between a shoulder |05 on the handle 95 and the yoke 9|. The yoke 9| is provided with a pair of ears |01 and |09 adapted to cooperate respectively with projections I and H3` on the contact lever 21.

In order to .relatch the operating lever 61 the handle 95 is manually rocked in a clockwise direction about its pivot 99 to the off position. Due to the cooperation of the projection IUI with the yoke 9| this movement of the handle 95 rocks the manual lever 85 in a counterclockwise direction. At this movement of the lever 85 the stud 93 engages a projection I|5 on the operating lever 61 and rocks said lever clockwise slightly beyond its latching position. The

cam slot 11 acting on the pin 19 rocks the switch arm 3| clockwise about the pivot 33 to its normal position. The parts are now in substantially the position indicated in Fig. 4, with the contact lever 21 in its manually opened position and the operating lever 51 in latched position.

The circuit breaker may now be manually closed by rotating the handle 95 in a counterclockwise direction from its orf (Fig. 4) position toward its on position rocking the lever in a clockwise direction, during which movement the ear H31 on the yoke 9| strikes the projection on the contact lever 21 and rocks the contact lever clockwise about its pivot 29. This moves the toggle 21-4I over center in a direction to cause the spring 43 to close the contacts with a snap action.

The contacts may be opened manually by movement of the handle in a clockwise direction to its of" position, which rocks the lever 85 counterclockwlse, This movement oi the lever 85 brings the ear |99 into contact with the projection ||3 and starts the contact lever 21 in a counterclockwise direction about the pivot 29, moving the toggle 21-4I over center to the left of the pivot 29, causing the contacts to open with a snap action. The mechanism is shown in the manually opened position in Fig. 4.

The contacts are closed manually from their manually opened position (Fig. 4) by rotating the handle 95 counterclockwise toward the "on" position, which movement rocks the lever 85 clockwise about its pivot 89. This causes the ear |01 to engage the projection and move the ,-1 toggle 21-4I overcenter toward the right of the pivot 29, whereupon the spring d3 rocks the contact lever 21 to close the contacts with a snap action.

Having described the preferred embodiment of the invention in accordance with. the patent statutes, it is to be understood that various changes and modications may be made in the structural details disclosed without departing from some of the essential `features of the invention. It is therefore, desired that the invention be interpreted as broadly as the prior art permits, and that it be limited only by what is expressly stated in the following claims.

I claim as my invention:

l. In a circuit breaker, relatively movable contacts, a switch arm movable to open and closed positions, a contact lever pivotally supported on the switch arm, releasable actuating means biased to move the switch arm to open position, an overcenter spring means cooperating with the contact lever to form a toggle, means on the releasable actuating means for engaging and moving the toggle over center in a direction to ro tate the contact lever in opening direction, and manually operable means operable to move the toggle over center to close the contacts.

2. In a circuit breaker, relatively movable con-- tacts. a switch arm movable to open and closed positions. a contact actuating lever pivotally supported on the switch arm, releasable actuating means for the switch arm, a spring biasing said actuating means to open position, an overcentor spring cooperating with the contact lever to form a toggle, means on the releasable actuating means enga-geable with the toggle to move said toggle over center in a direction to rotate the contact lever about its pivot on the switch arm in a direction to open the contact, and manually operable means engageable with the contact levei` when the switch arm is in closed position and operable to move said toggle over center in a direction to close the contacts.

3. In a circuit breaker, relatively movable contacts, a pivoted switch memberv operable to cause opening of the contacts, a Contact actuating lever pivotally mounted on said switch member, releasable actuating means for operating the switch member to cause opening of said contacts, current responsive means for releasing said actuating means, an overcenter spring cooperating with the contact actuating lever to form a toggle, and means movable in response to operation of the actuating means and engageable with said toggle when said actuating means is released to move the toggle over center in a direction to rotate the contact lever about its pivot in a direction to open the contacts.

4. In a circuit; breaker, relatively movable contacts, a switch arm operable to cause opening of said contacts, acontact actuating lever pivotally supported on the switch arm, spring biased actuating means releasable to operate the switch arm to cause opening of the contacts, a toggle including one arm of the contact actuating lever as an element thereof, and means on the actuating means for causing the toggle to rotate the contact actuating lever about its pivot to open the contacts when said actuating means moves to operate the switch arm.

5. In a circuit breaker, relatively movable contacts, a switch arm operable to cause opening of the contacts, a releasable actuating member having a cam thereon for operating said switch arm, a contact actuating lever pivotally mounted on the switch arm, an overcenter spring cooperating with the contact actuating lever to form a toggle disposed for movement with the switch arm, and means on the actuating member for causing said toggle to rotate the contact actuating lever on its pivot to open the contacts upon movement of the switch arm in an opening direction.

6. In a circuit breaker, relatively movable contacts. a switch arm having a normal position and movable to a second position to cause opening of said contacts, a releasable actuating member having a cam slot therein engaging a member on the switch arm to operate said Switch arm to said second position, a contact actuating arm pivotally mounted on the switch arm, an overcenter spring cooperating with the contact actuating arm to form a toggle, current responsive means operable to release the actuating member, means on the actuating member to operate said toggle in a direction to open the contacts. and manually operable means engageable with said toggle to operate said toggle in a direction to close the contacts when said switch arm is in said normal position.

'7. In a circuit breaker, relatively movable contacts, a switch arm operable to open and closed positions, a releasable actuating member for operating said switch arm, current responsive means operable to release Said actuating member. a contact actuating lever pivoted on the switch arm, an overcenter spring cooperating with the contact lever to form a toggle, means on the actuating member separately engageable with the toggle to operate the toggle in one direction to cause opening of the contacts upon movement of the switch arm to open position, and manually operable means for operating the toggle to open or to close the contacts while said switch arm is in closed position, said manually operable means also being operable to restore the actuating member to operating condition.

8. In a circuit breaker, relatively movable contacts, a switch arm operable to cause opening of the contacts, spring biased actuating means releasable to operate the switch arm, a bimetal element responsive to abnormal circuit conditions to release said actuating means, a contact actuating member pivoted on the switch arm, an overcenter spring cooperating with the contact actuating member to form a toggle, said toggle being movable with the switch arm for operating the contact actuating member to open the contacts, and manually operable means operable to reset the spring biased actuating means and also operable to cause the toggle to close the contacts.

9. In a circuit breaker, relatively movable contacts, a switch member operable to cause opening of the contacts, releasable means operable on the occurrence of an overload to operate the switch` member to open the contacts, a contact actuating member pivotally carried by the switch member, said contact actuating member having a plurality of projections thereon, a snap acting device comprising an overcenter spring movable with the switch member, a manually operable member, means on said manually operable member for engaging one of the projections to cause the snap acting device to move over center in a direction to open the contacts, and other means on said manually operable member for engaging another of said projections to cause the snap acting device to move over center in a direction to close the contacts.

10. In a circuit breaker, relatively movable contacts, a switch member movable from a normal to a second position to cause opening of said contacts, releasable actuating means for moving said switch member to open position to cause opening of the contacts, a contact actuating lever pivotally supported on the switch member, means supported on the switch member and operatively connected to the contact actuating lever for causing said lever to open and close the contacts with a snap action, and manually operable means separably engageable with the contact actuating lever and operable to cause opening and closing of the contacts with a snap action when said switch member is in normal position.

1l. In a circuit breaker, relatively movable contacts, a switch member operable from a normal position to a second position to cause opening of said contacts, actuating means biased to move said switch member to open position to cause opening of the contacts, a contact actuating lever mounted on the switch member, means comprising an overcenter spring mounted on the switch member and movable relative thereto for causing said actuating lever to open and close the contacts with a snap action, and manually operable means operable when the switch member is in normal position to cause opening and closing of the contacts.

12. In a circuit breaker, a pair of contacts one of which is movable to open and close the circuit of the breaker, a switch member having a contact actuating lever pivotally supported thereon, said switch member being movable from a normal position to a second position to cause opening of said contacts, manually operable means comprising a toggle separably engageable with the contact actuating lever when the switch member is in normal position to cause opening and closing movement of the contact actuating lever, means including an overcenter spring on the switch member to cause the contact actuating lever to open and close the contacts with a snap action, and means operable in response to predetermined conditions to cause movement of the switch member to said second position.

13. A circuit breaker comprising relatively movable contacts, a switch member having a normal position, a contact actuating arm pivotally mounted on said switch member, an overcenter spring carried by said switch member and engageable with said contact actuating arm for opening or closing the contacts with a snap action, manually operable means separably engageable with said contact arm and operable when said switch member is in said normal position to cause said overcenter spring to open and close said contacts, said switch member being movable to a second position to cause opening of said contacts independently of said manually operable means, and means operable in response to predetermined conditions to cause movement of said switch member to said second position, said manually operable means being operable to reset said switch member to its normal position.

14. In a circuit breaker, relatively movable contacts, a switch member having a normal position and movable to an open position to cause opening of the contacts, a spring biased actuating member for operating the switch member to open position in response to predetermined abnormal circuit conditions, a contact arm pivotally supported on the switch member, means including an overcenter spring carried by the switch member for operating the contact arm to open and close the contacts with a snap action and operable by the spring biased member to cause opening of the contacts, and manually operable means operable to cause the overcenter spring to open and close the contacts with a snap action.

HILLER D. DORFMAN. 

